drm/msm/dpu: remove debugfs support for misr

MISR support is the debug feature present in Snapdragon chipsets.
At the layer mixer and interfaces, MISR algorithm can generate CRC
signatures of the pixel data which can be used for validating
the frames generated. Since there are no clients for this feature,
strip down the support from the driver.

changes in v4:
	- changed introduced in the series
changes in v5:
	- update commit text with the need for the change(Sean)

Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>